A series of cyclic polythiaethers are being synthesized and tested as potential biotransport agents for heavy metal ions. The project includes the determination of complex stability constants, model membrane transport studies, and pharmacological studies on the Hg(II) complexes as well as related heavy metals. Also included in the project are spectral, electrochemical and kinetic studies on the Cu(II)-polythiaether complexes which mimic many of the properties of blue copper proteins.